Monday, October 3, 2011

Converting the Spirit Peugeot 406 Silhouette to N-Digital

I recently received a Spirit Peugeot 406 Silhouette for my birthday. I like the appearance of the car very much and have seen several favorable reviews of the car at various forum sites. However, I had no idea how the car would perform when converted to N-Digital on the Ninco track.
Upon removing the body from the chassis it's obvious that the car is relatively high-quality. It comes standard with adjustable vertical travel for the front axle, an adjustable separate motor/drive train pod and a motor rated at 23,000 RPM @ 14.8 Volts.

The N-Digital conversion was very easy, primarily because there is ample internal space for the decoder chip. I performed the usual operations for a simple N-Digital conversion:

- Removed the magnet.

- Lubricated the guide post, front axle holders, rear axle bushings, motor bushings and gears.

- Set the pod up loose, which always seems to help on Ninco track.

- Adjusted front axle travel to about 50%. Again, some travel is needed due to the uneven nature of Ninco track.

- Installed Ninco ProRace braids.

- Installed a N-Digital decoder chip that is set up for quick swapping.

The following photo shows the relative simplicity of the installation and how neat and tidy everything is.
Also worth noting is the fact that the geometry of the stock Spirit guide flag turns out to be ideal for excellent performance on the N-Digital/Ninco track.
So, with nothing more than the braid change and virtually no tuning to speak of, the Sprit Peugeot 406 turns out to be an outstanding performer on my very technical 60' N-Digital track. The motor is smooth with plenty of power. The car stays in the slot and handles corners as well as any car that I have. It is slightly faster than my best Ninco GT cars and is just a lot of fun to drive.

Well, if this conversion was so ho hum then why write home about it? Two reasons actually:

1.) The car turns out to be a great N-Digital performer, so I want to recommend it to N-Digital users;

2.) There is an issue -- related to the car's superior performance -- that N-Digital/Ninco users should be aware of.

It seems that the superior performance of this car, especially on Ninco track, may come a little bit on the sly. There are several characteristics of the chassis that become apparent very quickly:

- The motor has a relatively strong magnetic downforce. Even without the chassis magnet you can feel the pull when picking the car up off the track;

- The chassis rides very low on the track leaving little clearance. This is the result of a combination of chassis design and some very low-profile stock tires;

- The bottom of the motor case actually protrudes about 1/2 mm below the bottom surface of the pod. This accentuates the magnetic downforce and can possibly bring the motor case uncomfortably close to the rails.

The following three photos show rear and side views of ground clearance with the Spirit stock tires and the protrusion of the motor case through the pod opening.
Even with the magnet removed the feel of the car when driving is that of a magnet-equipped car. It's not stuck down like extreme magnet racing, but you can perceive the advantage when taking the corners. The back end will come out without "snapping" but you have to pay attention and be careful. There is no denying that the car is benefiting from the "enhanced" downforce. Regardless, the car is still a lot of fun to drive.

I did not experience any problems with the low chassis clearance on my track but you should be aware of how close to the rails the motor case is able to come. If this were to become a problem, especially on an N-Digital track, care must be taken to insure that the motor case cannot touch the rails under any circumstances. Damage to the N-Digital decoder chip could result if a short circuit were created by motor/rail contact.

One solution would be to cover the bottom of the motor case with electrical tape. In fact, this would be a good test to determine if the motor is touching the rails anywhere on your course. If there is no sign of scuffing or fraying of the tape then it could be removed or left in place as a safeguard.

If the motor is bottoming out as evidenced by damage to the electrical tape, a more effective solution would be installation of rear tires with a higher profile. The first photo below shows the car with Ninco 19 x 10 slicks in the rear. The difference is visually imperceptible, however, it did raise the chassis very slightly -- evidenced by a very small increase in lap times, which could also be related to tire grip. I can't be 100% sure.
The second photo below shows Slot.it 19 x 10 slicks on the rear. This tire has a much higher profile and the increased clearance is clearly evident. Note that the increased sidewall height required the use of a spacer (#6 nylon washer) under the rear body mounting post to avoid tire contact with the wheel well opening. This also had the effect of increasing lap times by about two to three tenths of a second, undoubtedly due to decreased magnetic force but I think also because of the tire compound. I think these are S2 (not great for Ninco track) but again, I'm not sure. The Slot.it P5 compound works quite well on Ninco track. In any event, it made the Peugeot's performance match up perfectly with the Ninco GT's on my track.
In summary:

There were no physical modifications required by this conversion. All stock parts are in tact, allowing the car to be returned to absolute stock condition at any time.

The car has a relatively low chassis clearance which can be a problem on Ninco track, but this is easily dealt with if necessary.

In my environment this car is a truly superior performer. If the prospect of increased magnetic downforce providing a performance advantage does not appeal to some N-Digital users, it is relatively easy and inexpensive to eliminate that advantage. The car will still handle quite well and will probably fit perfectly into existing GT race classes. So don't avoid this car because of that. Especially since these Spirit 1/32 slot cars are currently available from several slot retailers at a very attractive price. This is a great addition for any N-Digital user who likes this class of racing. Most importantly, it is really fun to drive.

by Michael Ashton